Human chondrosarcomas are malignant tumors of cartilage which present problems in surgical management related to difficulties in predicting the degree of malignancy from histologic appearance. Based on histologic findings, it may be difficult to determine whether a particular cartilage lesion is a benign cartilage tumor or a low grade chondrosarcoma. Human chondrosarcomas show great variability in growth rate, invasiveness, and tendency to metastasize. A precise, objective, quantitative method for assessing the degree of malignancy of chondrosarcomas is needed for the proper management of patients. Our recent studies indicate that in human chondrosarcomas, structural changes occur in the components of intercellular matrix which are related to the degree of malignancy of the tumors. The broad long range objective of the proposed studies is to develop a precise, objective method for assessing the degree of malignancy of human chondrosarcomas, and for distinguishing between benign cartilage tumors and low grade chondrosarcomas, from the structural changes in the components of the intercellular matrix. The development of such a method will involve studies of the composition and structure of proteoglycans and keratan sulfate isolated from chondrosarcomas, benign cartilage tumors, and normal human cartilage.